<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../assets/js/vue.js"></script>
</head>
<body>
    <div id="app">
        <input type="checkbox" :checked="getFlag()" @change="setFlag($event.target.checked)" >
        <ul>
            <li  v-for="(item,i) in arr">
                <input type="checkbox" v-model="arr[i]">
            </li>
        </ul>
    </div>
    <script>
        new Vue({
            el:"#app",
            data:{
                arr:[true,false,true,false,false]    
            },
            methods: {
                getFlag(){
                    return this.arr.every(item=>item);
                },
                setFlag(flag){
                    let newArr=[];
                    let size=this.arr.length;
                    newArr.length=size;
                    this.arr=newArr.fill(flag,0,size);
                }
            },
        })
    </script>
</body>
</html>